A drive pulley and a driven pulley of a belt type continuously variable transmission are formed from a fixed-side pulley half that is fixedly provided on a shaft and a movable-side pulley half that is axially slidably supported on a shaft and moves closer to or away from the fixed-side pulley half. Making the movable-side pulley half of the drive pulley move away from the fixed-side pulley half so as to increase the groove width of a V groove and making the movable-side pulley half of the driven pulley move closer to the fixed-side pulley half so as to decrease the groove width of a V groove changes the gear ratio to the LOW side, whereas making the movable-side pulley half of the drive pulley move closer to the fixed-side pulley half so as to decrease the groove width of the V groove and making the movable-side pulley half of the driven pulley move away from the fixed-side pulley half so as to increase the groove width of the V groove changes the gear ratio to the OD side.
When the movable-side pulley half is made to move closer to the fixed-side pulley half, the center of the V groove moves closer to the fixed-side pulley half, whereas when the movable-side pulley half is made to move away from the fixed-side pulley half, the center of the V groove moves away from the fixed-side pulley half; a displacement (that is, a misalignment) occurs in e axial direction between the centers of the V grooves of the drive pulley and the driven pulley accompanying the gear ratio being changed, and the misalignment increases and decreases between zero to a maximum value according to the gear ratio. When such a misalignment occurs, a section of a metal belt wound around the drive pulley and a section thereof wound around the driven pulley are displaced in the axial direction, and due to the rotating face of the metal belt deviating from a plane perpendicular to the axis there is the problem that the durability of the metal belt or the V-face of the pulley is affected.
In order to minimize the influence of misalignment of the belt type continuously variable transmission, an arrangement is known from Patent Document 1 below in which setting is carried out so that the misalignment becomes zero when the gear ratio of the belt type continuously variable transmission is in a TOP state, that is, when the load acting on the metal belt becomes a maximum, metal elements of the metal belt are made to bite into the V groove of the pulley in a straight line, and the behavior of the metal belt is thus stabilized, thereby enhancing the durability.
Furthermore, in order to minimize the influence of misalignment of the belt type continuously variable transmission, an arrangement is known from Patent Document 2 below in which the shape of the generatrix of the V-face of the pulley, which conventionally is straight, is formed into an arc shape that protrudes toward the metal belt side, and the side face of an element of the metal belt that comes into contact with the V-face of the pulley is formed into an arc shape that protrudes toward the pulley side.